Reland "Use SkSL "offset" to actually mean "line""

This reverts commit a909dd6b8d8d6540f382e848c959792379f19365.

Turns out those reportPendingErrors() calls I removed were in fact
necessary, just not on any of the CQ bots.

Change-Id: I8be0898ac0b41dbb703a35f705cac06ca716c0b7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/453077
Reviewed-by: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
17 files changed